Lifting-jack



J. G. HARR'FSUN.

LIFTING JACK. APPLICATION FILED JULY 18. 1919.

Patented Aug. 30,1921'.

swmwk L.) INVENTOR. Jerome G. Ha rr/on ATTORNMZ @F HELADELPHEA, PENNSYLVAN.

essence.

.application :Tied .uly le,

To all wwm @it may con/ccm:

Be it known that ll, JEROME HARRISON, a citizen of the United States residing at Philadelphia, in the county of hiladelphia and State of Pennsylvania., have invented new and useful improvements in Lifting# Jacks, of which the following is a specication.

The invention relates to lifting jacks and more particularly to that class of jacks known as screw jacks and has for an object to provide a lifting jack which can be easil operated to lift or jack up heavy loads wit the leastv amount of energy and a minimum amount of friction.

Among other features the invention comprehends a lifting jack in which use is made of a screw and a nut adapted to jack up or raise a'load upon the application of power to the screw, the relation of the nut to the screw being of a ball-bearing nature.

Still further the invention comprehends a lifting jack having a suitable handle and operating mechanism, with the handle adapted to be arranged in a compact out of the way position w en the jack is lnot in use and readily positioned to permit of applying energy to the jack proper .to accomplish the desired result.

In the further disclosure of the invention, `reference is to be had to the accompanying drawin constituting a part of this specification, 1n which similar characters of reference denote corresponding parts in all the views, and in which,-

Figure 1 is a vertical sectional view taken through the jack and parts -of the acs companying handle and operating mecha.- msm.

Fig. 2 is ahorizontal sectional view taken on the line 2 2 in Fig. 1.

Fig. 3-is a rear elevation of the nut with parts being broken away to disclose the underlying structure.

Flg. 4 is a horizontal sectional view taken on the line 4-4 in Fig. 3, and

Fig. 5- is a horizontal 'sectional View taken on the line l5--5 in Fig. 3.

' Referring more particularly to the views, I provide a' base 10 carrying a suitable housing 11, the lower part of which may be in the form of a casting and the upper part 11a of which is partially cylindrical and may be made of sheet metal or the like. The base 10 is formed with a lower race 12, preferably speeiiication of Letters Patent.

- gether wit Patented .ing. 30, 192i. 1919.. Serial e. Slilt.,

. made by machining the floor of the base and disposed within the lower part of the housing, is a toothed wheel 13 having the teeth la thereof proj ecting to one side of the upper face, the opposite face of the wheel being formed to rovide an upper race 15 which tothe lower race 12 and suitable balls 16 arranged between the races, provides a ball-bearing support for the toothed wheel 13. Disposed within the housing 11 is a screw 17 having square threads 18 the said screw being set upon the central portion of the toothed wheel 13 with the latter rigidly secured to the screw by a suitable machine screw 19 or the like. The screw 17 carries an encircling nut 20, the latter being preferably formed of a plurality of parts or sections 21, 22, including an oblique portion 23 roviding a passage-way 24 for a number of alls 25 adapted to be disposed in the passage-way24-and in passages 26, both of which communicate with the passage-way 24, one at the upper end and` the other at-the lower end thereof, the one constituting the in-going passage-way and. the other the outgoingor return passage-way, with the balls also arranged in the threads 18 of the screw which are encompassed by the nut. Thus in the operation of the screw and the resulting action of thenut the balls in the in-going, out-going and oblique passage-ways will be constantly moving therethrough' and around thel threads of the screw encircled by the nut, thereby reducing to a minimum the friction which otherwise would take place between the screw and the nut in the relative action thereof if the balls were not provided. By having the' passage-way 24 extending obliquely with the iii-going and out-coming passageways 26 tangential to the periphery of the screw proper, any possible chance of jamming of the balls between the screw and the lnut is prevented. It will of course be understood that instead of the balls shown and described any other form of anti-frictiondevices such as rollers or the like, may be emplo ed.

Encirc ing the screw 17 is a tubular upright 27, the lower end of which may be suitably connected with the nut or form an integral part thereof, as the case may be, said upright extending' upwardly beyond the upper Vpart 11-a of the housingl and carrying a shoe 28 with a suitable gulde ring 29 sef cured or formed with the upper part of the v30 including a crank 31 and a housing to closely encircle the upright and aid in guiding the same in its vertical movement, preventing very little if vany lateral Il; will now 'of course be apparentthat when the toothed wheel 13 is rotated on the ball-bearing of the base, resultant rotation of the screw 17 will take place and therefore the nut and its accompanying upright 27 will be raised to lift or jack up any load placed upon the shoe 28 with the ball-bearing construction between the nut and screw eliminating friction to a great extent and it will of course also be clear that the reversal of the rotation of the toothed wheel 13 will cause the nut to descend and therefore bring with it the upri ht and accompanying shoe 28.

vTo providel 01' the ready rotation of the toothed wheel 13, I employ a crank handle stem 32, the latter being preferably made in a plurality of sections 32", 32h, which can be disjointed to permit vvof easily taking the handle a'way\ when the jack is not in use. The section 321 furthermore, is provided with a plurality of hinged portions 33, enabling the handle 'to b'e swung to any desired angle relative to the horizontal supporting the base and also permitting of theV handle to be swung in an oblique plane, thereby to a great extent simulating a universal joint construction. The lower end of the handle, namely the section 32b has one of these hinges provided at' the juncture thereof with a stem 34 'of a pinion 35, suitably journaled in the housing 11 and meshing with the teeth 14 of the toothed wheel or gear 13, said stem 34 having a flattened portion 36 immediately adjacent the exterior of the housing, which flattened portion carries a ratchet wheel 37 normally engaged by a spring actuated pawl 38 mounted to swing on the housing 11 and having connected therewith a suitable wire 39, extending longitudinally along the stem 32 of the handle to connect with a handled operating element 40, including collars 41 loosely encirclin the stem 32 with a cross pin 42 throng the stem to limit the downward slidin movement of the operating element, the crank 31 limiting the upward sliding movement thereof. It will now be apparent that thepawl 38 normally engaging the ratchet wheel 37 will prevent reversal of movement of the handle in order that a load which has been jacked up can be held in its raised posi-` tion whereas o eration of the element 40, involving the sliding thereof upwardly along the stem, will disengage the pawl 38 from the wheel 37 thereby permitting of reversing the operation of the crank handle, thus lowering the jack.

It will of course be readily seen that the nut 20 is prevented from rotating because of ratchet mechanism on the the particular shape of the nut and the particular configuration in cross section of the upper part 11t of the housing 11, the nut as a unit providing an extension or projecting portion 20a which mi ht be said to be s uared and forms the oblique part 23 providing the passage-way 24, while the upper part 11a of the housing also has a s uared portion 11b which receives the square p0rtion or extension of the nut thereby preventing rotation of the latter relative to the former.

From the fore oing description it will be seen that the jack described provides a structure which will be ca able of lifting great weights or loads with comparative ease and that very little energy on the part of the operator is required to brin about the desired result, the handle of t e jack furthermore being so formed that it can be readily 'ack proper so e easily stored not in use.

Having described my invention,.I claim- 1. In a jack the combination with a base and a gear revolubly supported in the base, of a screw Vcarried by the gear and revoluble therewith, a nut encirclingthe screw, antifriction elements carried by the nut and movable into and out of rolling contact with the threads of the screw when the nut 'is advanced or retracted on the screw, an upright carried by the nut, a shoe on the upright,`a housing extending upwardly from said base, a handle, a pinion journaled in the base and meshing with saidgear, pawl and gear and associated with the handle for locking the gear against reverse movement and means on the handle for moving said pawl and ratchet mechanism into and out of operating position.

2. In a screw operated pressure producing device the combination with a revoluble screw and an upright, upright and including an offset portion, means for actuating the screw and a nut su porting the uprig t and inclosed by t e housing, said nut having an oli-set portion that the entire structure can -itting the oil-set portion of the housing to prevent rotation of the nut relative to the housing, said off-set portion of the nut having a straight diagonal passageway communicating with a plurality of end passage ways in turn having communication with the threads of the screw and anti-friction elements operating in the threads of the screw and through the passage ways of the nut.

In testimony whereof I alix my signature.

JEROME VGr. I'IARRISON;

removed from connection with the away in a small space when of a housing for the' 

